The kinesin superfamily is an extended family of related microtubule motor proteins. It can be classified into at least 8 subfamilies based on primary amino acid sequence, domain structure, velocity of movement, and cellular function. This family is exemplified by “true” kinesin, which was first isolated from the axoplasm of squid, where it is believed to play a role in anterograde axonal transport of vesicles and organelles (see, e.g., Goldstein, Annu. Rev. Genet. 27:319–351 (1993)). Kinesin uses ATP to generate force and directional movement associated with microtubules (from the minus to the plus end of the microtubule, hence it is a “plus-end directed” motor).
Within this functional group of kinesins resides a group of kinesins from several organisms that share significant sequence homology. These include Drosophila Klp67A, S. pombe BC2F12.13, S. pombe BC649.01c, S. cerevisiae Kip3, and HsKif1c.
Drosophila Klp67A has been shown to be a plus end-directed motor. This activity implicates KPL67A in the localization of mitochondria in undifferentiated cell types. In situ hybridization studies of the KLP67A mRNA during embryogenesis and larval central nervous system development indicate a proliferation-specific expression pattern. When affinity-purified anti-KLP67A antisera are used to stain blastoderm embryos, mitochondria in the region of the spindle asters are labeled. These data suggest that KLP67A is a mitotic motor with the role of positioning mitochondria near the spindle.
The discovery of a new kinesin motor protein, and more particularly, one having sequence homology to KLP67A, and the polynucleotides encoding it satisfies a need in the art by providing new compositions which are useful in the diagnosis, prevention, and treatment of cancer, neurological disorders, and disorders of vesicular transport.